Fusicoccum canker

Fusicoccum canker is a serious fungal disease caused by various species of the Fusicoccum genus. This pathogen is responsible for cankerous lesions on stems and branches, which can lead to the systemic decline of orchards, particularly affecting deciduous fruit trees and certain ornamental species.

The disease primarily targets trees such as peaches, almonds, pears, and apples. The fungus typically gains entry into the host plant through pruning wounds, frost cracks, hail damage, or other injuries that breach the protective bark layer, making orchard hygiene critical for prevention.

Symptoms initially manifest as localized areas of discolored, sunken bark. As the disease progresses, these lesions expand, often forming elongated cankers that encircle the branch. During moist weather, small black structures called pycnidia appear on the surface of the infected bark, releasing masses of spores that facilitate the spread of the pathogen.

The environmental development of Fusicoccum is closely linked to humidity and temperature. Spores are disseminated by splashing water, wind, and movement of equipment. Trees under stress—due to drought, nutrient deficiency, or cold injury—are significantly more susceptible to infection and exhibit faster decline once the fungus colonizes the inner bark.

The economic impact of this canker is severe, as it causes branch dieback and, in extreme cases, the death of entire trees. The pathogen disrupts the flow of nutrients and water, causing foliage to wilt and fruit production to plummet. If left unmanaged, a local infection can quickly become an epidemic across an entire orchard block.

Integrated management strategies are essential for control:

• pruning out infected branches at least 15-20 cm below the visible canker;
• disinfecting tools after each cut to prevent cross-contamination;
• applying copper-based fungicides to protect pruning wounds and during dormant periods;
• minimizing bark damage from frost and sunscald through proper site selection and trunk protection;
• maintaining vigorous tree growth through appropriate irrigation and soil nutrition programs.